Coilable rule and replacement cartridge therefor

ABSTRACT

A coilable rule is provided with a casing and a self sustaning replacement cartridge comprising a spool member rotatably mounted on a separate hub which has recesses in its end for non-rotatable engagement with truncated studs in the casing, a coiled blade, and a recoil spring attached to the blade and the hub. The spring tension is factory adjusted and maintained until assembled in the casing by a keeper.

[ Feb. 13, 1973 United States Patent 11 1 West [ COILABLERULE ANDREPLACEMENT 3m fimwfmy aua wQCBz was 999 111 WW l .1

3,214,836 11/1965 CARTRIDGE THEREFOR 3,318,550 5/1967 h 2,616,635 [75]Inventor: Robert F. West, New Bntaln, Conn. 3,041,004

1. 3,211,496 [73] Assignee: The Stanley Works, New Bntam,

Conn.

Primary Examiner-Stanley N. Gilreath Attorney-Prutzman, Hayes, Kalb &Chilton May 4, 1970 211 App]. No.: 34,080

, 122 Filed:

[57] ABSTRACT A coilable rule is provided with a casing and a selfsustaning replacement cartridge comprising a spool member rotatablymounted on a separate hub which has recesses in its end fornon-rotatable engagement with truncated studs in the casing, a coiledblade, and

242/lO7.l2, 107.2, 107.3, 107.6

a recoil spring attached to the blade and the hub. The Refemnces cuedspring tension is factory adjusted and maintained until assembled in thecasing by a keeper.

UNITED STATES PATENTS 242/107 6 8 Claims, 3 Drawing Figures....242/l07.3 ....33/l38 2,632,609 3/1953 3 ,482,798 12/1969 Kawaguchi3,216,117 l'l/l965 Stowell............................

'fPMENIEDmm ms INVENTOR ROBERT F. WEST I! lrlllflfff/Ill ATTORNEYSCOILABLE RULE AND REPLACEMENT CARTRIDGE THEREFOR This inventiongenerally relates to coilable rules and more particularly to animprovement in a coilable rule of the type shown and claimed in U.S.Pat. No. 3,216,117'issued Nov. 9, 1965 and assigned to the assignee ofthe present invention.

One of the objects of the present invention is to provide an improvedcoilable rule of a free hub design.

Another object of this invention is to provide a replacement cartridgefor a coilable rule wherein the coilable measuring blade and the recoilspring are factory preassembled on the hub in a pretensioned state sothat they may be field assembled in the casing in proper adjustmentwithout the use of special tools or assembly techniques.

Other objects will be in part obvious and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements and arrangement of parts which will beexemplified in the construction hereafter set forth.

In the drawings:

FIG. 1 is an exploded view, partly broken away, of a coilable ruleconstructed in accordance with the present invention;

FIG. 2 is an enlarged cross-sectional view of a replacement cartridgeincorporating the invention including a keeper for maintaining theintegrity of the replaceable cartridge before installation; and

FIG. 3 is an enlarged perspective view of the free hub constructionforming part of the invention.

Referring to the drawing in detail, FIG. 1 illustrates a coilable ruleembodying the present invention comprising a pair of mating casinghalves 2 and 4 which are joined together to define a chamber 6 forreceiving a spool 8. A coilable measuring blade 10 and a recoil spring12 are mounted on spool 8 with the, coiled measuring blade ll) beingsupported in coiled position on annularly disposed surfaces 13 providedby the side discs 14 of the spool 8 and the recoil spring supportedbetween the side discs 14 radially inwardly of the coiled measuringblade 10 as typically illustrated in the aforesaid U.S. Pat. No.3,216,117. The casing is provided with a mouth 16 adjacent the bottomwall 18 through which the measuring blade 10 passes when the latter isextended and retracted.

As shown, the coilable rule is provided with a manually operated brakemember 20 to lock the tape blade 10 in adjusted extended position asmore fully disclosed and claimed in my U.S. Pat. No. 3,214,836.

The casing halves 2, 4 are generally mirror images of each other withcasing half 2 being provided with hollow posts 22 which are received inmating sockets 24 provided in casing half 4. Fasteners such as screwsmay be passed through the sockets 24 and threaded into the posts 22 tohold the casing together.

According to one aspect of this invention, the inner end of the recoilspring 12 is anchored to a free hub 28 by being inserted in a nonradialslot 30 in the hub. The ends of free hub 28 which may be formed of asuitable molded plastic, are provided with apertures 32 of noncircularor square cross section which receive the mating truncated studs 26respectively provided on casing halves 2, 4 to hold the hub againstrotation while permitting it to be readily removed for replacement.

The inner end of the measuring blade 10 is connected to the outer end ofrecoil spring 12 in any suitable manner so as to automatically beretracted into coiled position in the chamber under the bias of therecoil spring when the measuring blade is released from any of itsextended positions. The free end of the measuring blade is provided witha suitable hook 31, as shown in FIG. 1, to maintain the free end of theblade accessible at the mouth of the casing when the measuring blade 10is retracted into the casing.

in measuring tapes of the general type described, the measuring blade10, or the recoil spring 12, is sometimes damaged in use requiringreplacement. 1n the past, such replacement has required special assemblyskill or a trial and error procedure to adjust the recoil spring 12 to aproper level of tension for satisfactory performance. Because of thedifficulties in replacing the blade and achieving the proper tensionlevel, the entire rule is frequently discarded in favor of a newcoilable rule rather than repaired.

The present invention provides a novel construction which makes itpossible to replace a damaged blade by installing a factory assembledreplacement cartridge which can be readily accomplished without specialtools or skills. As shown in FIG. 2, such a replacement cartridgeincludes a spool assembly having a spool and a free hub 28 to which theinner end of the recoil spring 12 is secured with the recoil springbeing factory adjusted to a precisely fixed level of tension so that therepaired rule will operate with the same level of performance as a newrule.

In the replacement cartridge of FIG. 2, the spool comprises aself-sustaining construction to maintain its assembled relationshipduring shipment and installation. As illustrated, the spool is formed ofa pair of molded plastic identical disc members 34 providing peripheralshoulders 36 for supporting the innermost coil of the measuring blade 10when it is in its coiled position. The shoulders 36 of each of the discmembers 34 are extended laterally to provide a pair of circumferentiallyspaced arcuate flanges 38 disposed apart. The two disc members 34 areassembled with the flanges 38 thereof being interdigitated and thebeaded ends 40 thereof snap-fitted into mating slots 44 provided in theopposite disc member 34.

The outer side of each of the discs is provided with an annular rib 46which engages the inner surface of the casing halves 2 and 4 to providea bearing surface of uniform limited frictional resistance for smoothoperation of the rule. Each of the discs is provided with a centralannular flange 48 which is journalled on the free hub 28 as shown inFIG. 2 and with pairs of apertures 50 for purposes hereinafter morefully described.

The cavity between the discs radially inwardly from the flanges 38provides a chamber for recoil spring 12 and the flanges arecircumferentially spaced as at 49 so that the outer end of the recoilspring may pass therethrough and be connected to the inner end of themeasuring blade 10.

With the replacement cartridge of FIG. 2 assembled in the factory withthe recoil spring 12 adjusted to the desired tension and the measuringblade 10 coiled about the flanges 38, a keeper 52 is applied asindicated in FIG. 2. The keeper may be formed of sheet metal or moldedfrom a suitable plastic material. The keeper 52 is provided with anoncircular projection 54 which is nonrotatably received in an end offree hub 28 and is also provided with one or more inwardly projectinglegs 56 which are received in the apertures 50 of a disc member 34 tothereby prevent relative rotation of the free hub with respect to thespool during shipment and assembly in the rule as a replacement unit.The keeper 52 is also shown as being provided with a pair of resilientouter arms 57 which snap over the outer edge 35 of one of the discs 34to secure the keeper on the spool and overlie the coiled measuring bladeto prevent it from unwinding during shipment and assembly.

With the assembly shown in FIG. 2, all that is required to replace theblade is to disassemble the easing halves 2, 4, remove the old spooltogether with the measuring blade 10, the coiled spring 12 and the freehub 28, insert the replacement cartridge of FIG. 2 with the end of themeasuring blade 10 projecting through the mouth 16 of the casing and thehub of the cartridge engaged with the truncated stud 26 of theappropriate casing half. When so assembled, the keeper 52 may beremoved, the other casing half assembled over the replacement cartridgeand the fasteners reinstalled to maintain the casing halves together.

It will be apparent that the replacement cartridge may be installedwithout loss of the proper factory adjusted tension of the recoil spring12 so that the tape with the repaired rule performs with the quality ofa new rule.

From the foregoing it will be readily apparent that the presentinvention provides an improved coilable rule having a free hubconstruction and further provides for the repair of the rule with areplacement cartridge factory adjusted to provide new rule performancein a repaired rule.

As will be apparent to persons skilled in the-art, variousmodifications, adaptations and variations of the foregoing specificdisclosure can be made without departing from the teachings of thepresent invention.

lclaim:

l. A replacement cartridge for a coilable rule comprising aform-sustaining spool mounting a coiled measuring blade, said spoolhaving a centrally disposed aperture, a removable hub received withinsaid aperture, a recoil spring having one end secured to said hub andthe other end secured to the inner end of said measuring blade, and akeeper for maintaining the measuring blade, the recoil spring and thehub in fixed relation relative to each other and to the spool, and meansfor securing said keeper against rotation relative to said spool.

2. The replacement cartridge of claim 1 wherein a ledge extends betweenthe side walls of the spool, said ledge mounting the coiled measuringblade thereon.

3. The replacement cartridge of claim 1 wherein said keeper provides apair of outer arms resiliently engageable with the outer surface of saidcoiled measuring blade.

4. The replacement cartridge of claim 3 wherein the spool is providedwith side walls extending beyond the coiled measuring blade and saidpair of outer arms snap over the edge of one of said side walls toretain the keeper on the spool.

5. The replacement cartridge of claim 1 wherein a noncircular centralrecess is provided in the end of said hub and a mating noncircularprojection on said keeper is engaged in said recess to non-rotatably fixthe keeper relatively to said hub.

6. In a measuring device of the coilable rule type having a casingcomprising a pair of casing halves defining a chamber therein, a recoilspring received in the chamber and a coilable measuring blade connectedto said spring to be retracted into coiled position in the chamber underthe bias of said recoil spring and extended through an opening in saidcasing against the bias of said recoil spring; the improvementcomprising a removable spool assembly incorporating a spool upon whichsaid blade is coiled, and a hub member rotatably mounting said spool andto which the inner end of the recoil spring is secured for simultaneousremoval and installation of said spool assembly, blade and spring insaid casing, said casing and the ends of said hub member being providedwith mating recess and projection means to mount said hub member in saidcasing and to fix said hub member against rotation relative to saidcasing under the bias of the recoil spring.

7. The device of claim 6 wherein the recess means is provided in theends of said hub member and the projection means is a truncated studcentrally disposed on a wall of one of said casing halves.

8. The device of claim 7 wherein a truncated stud is provided on theconfronting wall of each of said casing halves.

1. A replacement cartridge for a coilable rule comprising aform-sustaining spool mounting a coiled measuring blade, said spoolhaving a centrally disposed aperture, a removable hub received withinsaid aperture, a recoil spring having one end secured to said hub andthe other end secured to the inner end of said measuring blade, and akeeper for maintaining the measuring blade, the recoil spring and thehub in fixed relation relative to each other and to the spool, and meansfor securing said keeper against rotation relative to said spool.
 1. Areplacement cartridge for a coilable rule comprising a form-sustainingspool mounting a coiled measuring blade, said spool having a centrallydisposed aperture, a removable hub received within said aperture, arecoil spring having one end secured to said hub and the other endsecured to the inner end of said measuring blade, and a keeper formaintaining the measuring blade, the recoil spring and the hub in fixedrelation relative to each other and to the spool, and means for securingsaid keeper against rotation relative to said spool.
 2. The replacementcartridge of claim 1 wherein a ledge extends between the side walls ofthe spool, said ledge mounting the coiled measuring blade thereon. 3.The replacement cartridge of claim 1 wherein said keeper provides a pairof outer arms resiliently engageable with the outer surface of saidcoiled measuring blade.
 4. The replacement cartridge of claim 3 whereinthe spool is provided with side walls extending beyond the coiledmeasuring blade and said pair of outer arms snap over the edge of one ofsaid side walls to retain the keeper on the spool.
 5. The replacementcartridge of claim 1 wherein a noncircular central recess is provided inthe end of said hub and a mating noncircular projection on said keeperis engaged in said recess to non-rotatably fix the keeper relatively tosaid hub.
 6. In a measuring device of the coilable rule type having acasing comprising a pair of casing halves defining a chamber therein, arecoil spring received in the chamber and a coilable measuring bladeconnected to said spring to be retracted into coiled position in thechamber under the bias of said recoil spring and extended through anopening in said casing against the bias of said recoil spring; theimprovement comprising a removable spool assembly incorporating a spoolupon which said blade is coiled, and a hub member rotatably mountingsaid spool and to which the inner end of the recoil spring is securedfor simultaneous removal and installation of said spool assembly, bladeand spring in said casing, said casing and the ends of said hub memberbeing provided with mating recess and projection means to mount said hubmember in said Casing and to fix said hub member against rotationrelative to said casing under the bias of the recoil spring.
 7. Thedevice of claim 6 wherein the recess means is provided in the ends ofsaid hub member and the projection means is a truncated stud centrallydisposed on a wall of one of said casing halves.